Saving startup file does not effect startup
I believe it's a bug of blender I reported here, which already fixed in the current development branch and will be backported to 2.83 LTS version (fix included in version &gt;= 2.83.4). For a workaround, after you do save your startup file, then navigate to preferences dialog and do any setting to get userpref.blend file generated in the blender user config folder, then it should works.